如何在Rails 4 App中启用CORS

Question

我正要把我的头发拉出来...我从早上起就试图在这个Rails应用程序中启用CORS,它只是不起作用.我试过这个,使用 Rack Cors Gem,这个答案和这篇文章都没有成功.

有人能指出我正确的方向吗？

这是我的js:

      var req = new XMLHttpRequest();

      if ('withCredentials' in req) {
            // req.open('GET', "https://api.github.com/users/mralexgray/repos", true);
            req.open('GET', "http://www.postcoder.lc/postcodes/" + value, true);
            // Just like regular ol' XHR
            req.onreadystatechange = function() {
                if (req.readyState === 4) {
                    if (req.status >= 200 && req.status < 400) {
                        // JSON.parse(req.responseText) etc.
                        console.log(req.responseText);
                    } else {
                        // Handle error case
                    }
                }
            };
            req.send();
        }

当我尝试这个url(来自外部客户端):https://api.github.com/users/mralexgray/repos工作正常,我假设问题出在我的Rails API上.我错了吗？

编辑:目前我在我的控制器中有这个:

skip_before_filter :verify_authenticity_token
before_filter :cors_preflight_check
after_filter :cors_set_access_control_headers

# For all responses in this controller, return the CORS access control headers.
def cors_set_access_control_headers
  headers['Access-Control-Allow-Origin'] = '*'
  headers['Access-Control-Allow-Methods'] = 'POST, GET, OPTIONS'
  headers['Access-Control-Max-Age'] = "1728000"
end

# If this is a preflight OPTIONS request, then short-circuit the
# request, return only the necessary headers and return an empty
# text/plain.

def cors_preflight_check
  headers['Access-Control-Allow-Origin'] = '*'
  headers['Access-Control-Allow-Methods'] = 'POST, GET, OPTIONS'
  headers['Access-Control-Allow-Headers'] = 'X-Requested-With, X-Prototype-Version'
  headers['Access-Control-Max-Age'] = '1728000'
end

Answer 1

你应该使用机架式的

它提供了一个很好的DSL,用于你的config/application.rb,而不是凌乱的标题工作和过滤器之前.

一个非常宽容的将如下,但当然,你将不得不量身定制它.

use Rack::Cors do
  allow do
    origins '*'
    resource '*', headers: :any, methods: :any
  end  
end

Answer 2

Rack :: Cors为跨源资源共享提供支持

启用rackcors的步骤:

1.添加宝石到你的Gemfile:

gem 'rack-cors'

2.将以下代码添加到config/application.rb

# if you are using Rails 3/4
config.middleware.insert_before 0, "Rack::Cors" do
  allow do
    origins '*'
    resource '*', :headers => :any, :methods => :any
  end
end
# if you are using Rails 5

config.middleware.insert_before 0, Rack::Cors do
  allow do
    origins '*'
    resource '*', headers: :any, methods: :any
  end
end